Flaps and V-Tails of Death

"Eric Greenwell" wrote in message
Wallace Berry wrote:

So, I'd have to say that all the bad things I've been told about landing
flaps on gliders and V-tails are definitely untrue with respect to the
HP-16.

If you believe that, perhaps you haven't been told "all the bad things".
For example, I've had HP pilots tell me getting sucked up into a cloud
can be "awkward" to deal with when all you've got is flaps.

My first and only flight in an HP went like Mr. Berry's; even so, I hope
anyone beginning to fly a flaps only glider gets thorough checkout,
because there are ways to go wrong.

No offense, Eric, but speaking from the vantage point of one with all his
1-26 glide-ratio time in flaps-only ships (C-70, HP-14, Zuni), the more
powerful the flaps, the _less_ 'exciting' it need be if you allow yourself
to get sucked into a cloud. (For those unfamiliar with lift in the western
U.S., streets miles long and wide containing lift exceeding 10 knots are not
uncommon, and 'getting sucked into a cloud' _can_ happen, even if relatively
savvy and switched on...scale effects, new experience learning curves, etc.)

Can we take as a given that what's 'thrilling' about IFR flight with a VFR
panel is the very real possibility of pulling wings off in the ensuing
spiral dive? If that's true, then the more drag you have available...and
flapped HP's tend to have a LOT of disposable drag [a great thing as Wallace
B. better understands now, :-)]...the less thrilling blind flight. My HP-14
wouldn't exceed 55 knots (as I recall) with full flaps when left to its own
(hands-off) devices for minutes on-end. Sure, it took on some interesting
attitudes as it alternately nosed up, stalled, fell off on a wing, regained
speed, nosed up...etc., but there was no way it was ever going to come close
to maneuvering speed. To avoid the repeated stalling, all one needed to do
was hold 40 knots with full flaps (required forward stick). You'd
eventually end up in a steep spiral, but, so what?

My Zuni is less forgiving (considerably weaker flaps...i.e. less drag than
the HP-14) in this regard, and will pretty soon exceed 75 knots
hands-off-the-stick in the zoom, stall, fall off sequence, but like the HP
is utterly innocuous if trimmed aft w. full flaps and held at 40 (or 45 or
whatever one is comfortable with). Again, you're likely to eventually end
up in a tight spiral if using this technique, but you're not going to pull
the wings off.

IMHO, playing imaginary mind games (and backed up by considerable
experimentation over the years), my personal adrenaline level will be a lot
lower in a flaps-only ship having 'adequate drag' (and I know of no 15-meter
flap-only ships that do not) than in a spoilers-only ship if I envision
being in a big, turbulent cloud with a VFR panel. For the record, I'm aware
of the 'benign spiral mode.'

Actually, I suspect 'flapped cloud safety' comes not so much the flaps
as-such, but from their high level of drag. Imagine a tail-chute-only of
'ridiculously large diameter' to see what I mean...likewise, 'ridiculously
large spoilers'. For non-U.S. pilots, the most powerful spoiler-only
gliders I know of are the Schweizer 1-34 and 2-32, both of which have
terminal-velocity-limiting dive brakes. Personally, I'd much rather come
out the bottom of a cloud doing 40 knots in a spiral than at Vne more or
less vertically. Adrenaline may have its place in the human condition, but
I prefer to keep mine out of the cockpit!

Regards,
Bob - you can't have too much disposable drag - Whelan


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